Battery retention system for a power tool

ABSTRACT

A battery retention system for a power tool having a motor, a drive mechanism coupled to the motor, and an output element coupled to the drive mechanism. The battery retention system includes a battery pack for powering the motor, the battery pack being removably coupled to the power tool. The battery retention mechanism also includes a first mating feature for coupling the battery pack to the power tool and a second mating feature for coupling the battery pack to the power tool independently from the first mating feature. The second mating feature is configured to couple the battery pack to the power tool when the first mating feature is disengaged.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/391,381 filed on Oct. 8, 2010, the entire contents of which areincorporated herein by reference.

BACKGROUND

The present invention relates to a battery retention system forretaining a battery pack in a power tool.

A battery pack may be connected to a power tool such as a screwdriver, adrill, an impact driver, a ratchet, a reciprocating saw, etc. to providepower to the tool. Such power tools include a motor and typicallygenerate vibrations as a result of use. A battery pack is typicallyretained in the tool by way of a latch mechanism. The latch mechanism issubject to possible failure due to fatigue, particularly when used intools that generate vibrations.

SUMMARY

In one aspect, the invention provides a battery retention system for apower tool having a motor, a drive mechanism coupled to the motor, andan output element coupled to the drive mechanism. The battery retentionsystem includes a battery pack for powering the motor. The battery packis removably coupled to the power tool. The battery retention mechanismalso includes a first mating feature for coupling the battery pack tothe power tool and a second mating feature for coupling the battery packto the power tool independently from the first mating feature. Thesecond mating feature is configured to couple the battery pack to thepower tool when the first mating feature is disengaged.

In another aspect, the invention provides a battery retention system fora power tool. The battery retention system includes a power tool havinga motor, a drive mechanism coupled to the motor, and an output elementcoupled to the drive mechanism. The battery retention system alsoincludes a battery pack for powering the motor, the battery pack beingremovably coupled to the power tool. The battery retention system alsoincludes a first mating feature associated with the power tool andreceived by the battery pack for coupling the battery pack to the powertool and a second mating feature associated with the battery pack andreceived by the power tool for coupling the battery pack to the powertool. One of the first mating feature and the second mating feature isconfigured to provide a backup to the other of the first mating featureand the second mating feature in the event that the other of the firstmating feature and the second mating feature is disengaged.

In yet another aspect, the invention provides a battery retention systemfor a power tool. The battery retention system includes a power toolhaving a motor, a drive mechanism coupled to the motor, and an outputelement coupled to the drive mechanism. The battery retention systemalso includes a battery pack for powering the motor, the battery packbeing removably coupled to the power tool, a rail disposed on one of thebattery pack and the power tool, a latch disposed on one of the batterypack and the power tool, and a latch contact surface for receiving thelatch to hold the battery pack with respect to the power tool. Thebattery retention system also includes a spring having at least onespring arm for engaging the rail to hold the battery pack with respectto the power tool. The latch holds the battery pack with respect to thepower tool independently of the spring.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a power tool having a battery pack and abattery retention system embodying the invention.

FIG. 2 is a perspective view of a portion of the power tool of FIG. 1having the battery retention system.

FIG. 3 is a perspective view of the battery pack of FIG. 1.

FIG. 4 is an exploded perspective view of the battery pack of FIG. 3.

FIG. 5 is a top view of the battery pack of FIG. 3.

FIG. 6 is a perspective view of the battery pack of FIG. 3 including aportion of the battery retention system.

FIG. 7 is a side view of the battery pack of FIG. 3 including a portionof the battery retention system.

FIG. 8 is a bottom view of the battery pack of FIG. 3.

FIG. 9 illustrates a battery pack for use with a variety of toolsemploying the battery retention system of FIGS. 1-8.

Before any constructions of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other constructions and of being practicedor of being carried out in various ways. Also, it is to be understoodthat the phraseology and terminology used herein are for the purpose ofdescription and should not be regarded as limiting.

DETAILED DESCRIPTION

FIGS. 1-8 illustrate a tool 10 having a battery retention system 12 anda battery pack 14 received and retained by the battery retention system12. With reference to FIG. 2, the battery retention system 12 includes acavity 16 located in a distal end 18 of the tool 10 for receiving thebattery pack 14. With reference to FIG. 8, the battery pack 14 includesrails 20 a, 20 b and a pair of latches 22 a, 22 b. A biasing member 24is disposed in the cavity 16 for engaging the rails 20 a, 20 b to retainthe battery pack 14, and a pair of latch contact surfaces 26 a, 26 b arerecessed into the tool 10 adjacent the cavity 16 for receiving andengaging the latch 22 a, 22 b if the biasing member 24 fails, thusproviding a secondary retaining mechanism, as will be described ingreater detail below.

In the illustrated construction, the tool 10 is a battery-poweredmulti-tool (FIG. 1). In other constructions, the battery retentionsystem 12 may be employed with other types of battery-powered tools,particularly with tools having a motor such that the battery issubjected to vibrations from use of the tool. For example, other toolsfor applications such as drilling, fastening, cutting, and materialremoval may be employed. For example, as illustrated in FIG. 9, thebattery retention system 12 may be employed with battery-powered drills12 a, impact drivers 12 b, ratchet wrenches (not illustrated) andreciprocating saws 12 c.

With reference to FIG. 1, the tool 10 includes a housing 30, a motor 32positioned substantially within the housing 30, a drive mechanism 34mechanically coupled to the motor 32, and an output element 36mechanically coupled to the drive mechanism 34. The motor 32 is operableto drive the drive mechanism 34, such as an eccentric drive mechanism,and the output element 36, such as an oscillating member of anoscillating tool, as illustrated. The output element 36 produces anoutput force when driven by the drive mechanism 34. It is to beunderstood that in other constructions, other drive mechanisms, such asgear reduction systems, and other output elements, such as a screwdriver bit, may be employed, as discussed above.

The tool 10 also includes a grip 38 formed in the housing 30 and aswitch 40 supported by the housing 30 generally opposite the grip 38.The switch 40 is electrically coupled between the battery pack 14 andthe motor 32 to selectively provide power to the motor 32. Actuating theswitch 40 thereby controls operation of the tool 10 by powering themotor 32 which in turn drives the output element 36.

As illustrated in FIG. 2, the biasing member 24 is disposed in thecavity 16 proximate the distal end 18 of the tool 10 and is formed as asingle piece, such as from a metal, although other suitable materialsmay be used in other constructions. The biasing member 24 includes afirst spring arm 24 a, a second spring arm 24 b and a cross member 24 cconnecting the first spring arm 24 a and the second spring arm 24 b. Thespring arms 24 a, 24 b generally extend parallel to a central orlongitudinal axis A (FIG. 1) of the tool 10 and extend from the crossmember 24 c generally towards the distal end 18 of the tool 10. Eachspring arm 24 a, 24 b includes a respective projection 44 a, 44 bextending into the cavity 16 and generally transverse to, and morespecifically generally perpendicular to, the longitudinal axis A forengaging the rails 20 a, 20 b, respectively, of the battery pack 14 in aprimary locking engagement. In other constructions, the first and secondspring arms 24 a, 24 b may be formed from separate pieces of materialsuch that the biasing member 24 is formed from multiple pieces.

A pair of terminals 46 are disposed in the cavity 16 and extend into thecavity 16 towards the distal end 18 and generally parallel to thelongitudinal axis A. The terminals 46 are for electrically connectingthe tool 10 to the battery pack 14, as will be described in greaterdetail below.

With further reference to FIG. 2, the housing 30 has an inner surface 48and an outer surface 50. The latch contact surface 26 a, 26 b is locatedon the inner surface 48 adjacent a latch-receiving recess 52 a, 52 b.The latch-receiving recess 52 a, 52 b includes a depth D measuredgenerally parallel to the longitudinal axis A of the tool 10 between thelatch contact surface 26 and an opposite surface adjacent thelatch-receiving recess 52 a, 52 b, as shown in FIG. 2. The depth D isdimensioned such that the latch contact surface 26 a, 26 b does notlockingly engage the latch 22 a, 22 b of the battery pack 14 if thebiasing member 24 is in locking engagement with the battery pack 14. Thedepth D is dimensioned such that the latch contact surface 26 a, 26 bforms a locking engagement with the latch 22 a, 22 b of the battery pack14 if the biasing member 24 fails. Thus, the biasing member 24 providesa primary locking engagement mechanism and the latch contact surface 26provides a conditional secondary locking engagement mechanism only. Thatis, the secondary locking engagement mechanism only acts as a lockingengagement mechanism when the primary locking engagement mechanismfails. Thus, the secondary locking engagement mechanism is provided as abackup for the primary locking engagement mechanism. In otherconstructions, the primary locking engagement mechanism and thesecondary locking engagement mechanism may act simultaneously to providea locking engagement between the battery pack 14 and the tool 10.

The battery retention system 12 also includes rubber pads 54 disposed onthe inner surface 48 of the housing 30 for cushioning the battery pack14 against vibrations of the tool 10. The rubber pads 54 may beovermolded into the inner surface 48 of the housing 30. In otherconstructions, the rubber pads 54, or cushions, may be formed of otherelastic or dampening materials such as silicone, polyurethane elastomer,and other suitable polymers. The battery retention system 12 alsoincludes a chamfer 56 adjacent an edge of the housing 30 defining thedistal end 18. The chamfer 56 provides a lead-in to the cavity 16 forinhibiting the rubber pads 54 from lifting when the battery pack 14 isinserted into the cavity 16. Furthermore, the chamfer 56 centers thebattery pack 14 to inhibit the battery pack 14 from being twistable, orrotatable, as it is removed from the cavity 16.

FIGS. 3-8 illustrate the battery pack 14 for use with the tool 10. Inthe illustrated construction, the battery pack 14 is a lithium-based,rechargeable battery pack and is removably and interchangeably connectedto the tool 10 to provide power during operation and to facilitaterecharging of the battery pack 14 when not in use. In someconstructions, the battery pack 14 may be used with other types ofcordless, battery-powered tools or devices not specifically discussedherein.

The illustrated battery pack 14 includes a casing 62, an outer housing60 coupled to the casing 62, and a plurality of battery cells 64 (FIG.4) positioned within the casing 62. The casing 62 is shaped and sized tofit within the cavity 16 in the tool 10 to connect the battery pack 14to the tool 10. The casing 62 includes an end cap 66 to substantiallyenclose the battery cells 64 within the casing 62. The illustrated endcap 66 includes two power terminals 68 configured to mate withcorresponding power terminals 78 extending from the tool 10. In otherconstructions, the end cap 66 may include terminals that extend from thebattery pack 14 and are configured to be received in receptaclessupported by the tool 10. The end cap 66 also includes sense orcommunication terminals 70 (shown in FIG. 5) that are configured to matewith corresponding terminals from the tool 10. The terminals 70 coupleto a battery circuit (not shown). The battery circuit can be configuredto monitor various aspects of the battery pack 14, such as packtemperature, pack and/or cell state of charge, etc. and can also beconfigured to send and/or receive information and/or commands to and/orfrom the tool 10. In one construction, the battery circuit operates asillustrated and described in U.S. Pat. No. 7,157,882 entitled “METHODAND SYSTEM FOR BATTERY PROTECTION EMPLOYING A SELECTIVELY-ACTUATEDSWITCH,” issued Jan. 2, 2007, the entire contents of which are herebyincorporated by reference. In another construction, the battery circuitoperates as illustrated and described in U.S. Pat. No. 7,589,500entitled “METHOD AND SYSTEM FOR BATTERY PROTECTION,” issued Sep. 15,2009, the entire contents of which are also hereby incorporated byreference.

The casing 62 and the receptacles 72 substantially enclose and cover theterminals 46 on the tool 10 when the pack 14 is positioned within thecavity 16. That is, the battery pack 14 functions as a cover for thecavity 16 and terminals 46 of the tool 10. Once the battery pack 14 isdisconnected from the tool 10 and the casing 62 is removed from theopening, the battery terminals 46 on the tool 10 are generally exposedto the surrounding environment, as shown in FIG. 2.

The outer housing 60 is coupled to an end of the casing 62 substantiallyopposite the end cap 66 and surrounds a portion of the casing 62. In theillustrated construction, when the casing 62 is inserted into orpositioned within the corresponding cavity 16 in the tool 10, the outerhousing 60 generally aligns with the outer surface 50 of the tool 10. Inthis construction, the outer housing 60 is designed to substantiallyfollow the contours of the tool 10 to match the general shape of thetool 10. In some constructions, such as the illustrated construction,the casing 62 is inserted into the grip portion 38 of the power tool 10.In such constructions, the outer housing 60 generally increases (e.g.,extends) the length of the grip 38 of the tool 10.

As shown in FIG. 4, the battery pack 14 includes three battery cells 64positioned within the casing 62 and electrically coupled to theterminals 40. The battery cells 64 provide operational power (e.g., DCpower) to the tool 10. In the illustrated construction, the batterycells 64 are arranged in series, and each battery cell 64 has a nominalvoltage of approximately four-volts (4.0V), such that the battery pack14 has a nominal voltage of approximately twelve-volts (12V). The cells32 also have a capacity rating of approximately 1.4 Ah. In otherconstructions, the battery pack 14 may include more or fewer batterycells 64, and the cells 64 can be arranged in series, parallel, or aseries and parallel combination. For example, the pack 14 can include atotal of six battery cells 64 in a parallel arrangement of two sets ofthree series-connected cells 64. The series-parallel combination ofbattery cells creates a battery pack having a nominal voltage ofapproximately 12V and a capacity rating of approximately 2.8 Ah. Inother constructions, the battery cells 64 may have different nominalvoltages, for example, 3.6V, 3.8V, 4.2V, etc., and/or may have differentcapacity ratings, for example, 1.2 Ah, 1.3 Ah, 2.0 Ah, 2.4 Ah, 2.6 Ah,3.0 Ah, etc. In other constructions, the battery pack 14 can have adifferent nominal voltage, for example, 10.8V, 14.4V, etc. In theillustrated construction, the battery cells 64 are lithium-ion batterycells having a chemistry of, for example, lithium-cobalt (Li—Co),lithium-manganese (Li—Mn), or Li—Mn spinel. In other constructions, thebattery cells 64 may have other suitable lithium or lithium-basedchemistries.

With particular reference to FIGS. 6-8, the battery pack 14 includes apair of rails 20 a, 20 b extending from the battery pack 14. The springarms 24 a, 24 b of the biasing member 24 engage the rails 20 a, 20 b,respectively, to form the primary locking engagement mechanism toreleasably secure the battery pack 14 to the tool 10.

In the illustrated construction, two actuators 58 a, 58 b and twolatches 22 a, 22 b are formed in the outer housing 60 of the batterypack 14. The latch contact surfaces 26 a, 26 b of the tool 10 engage therespective latches 22 a, 22 b if the biasing member 24 disengages, e.g.,breaks, is released or otherwise fails to provide a locking engagementbetween the battery pack 14 and the tool 10. Thus, the latches 22 a, 22b form the secondary locking engagement mechanism to releasably securethe battery pack 14 to the tool 10. Each latch 22 aa, 22 b engages thecorresponding latch contact surface 26 a, 26 b formed in the tool 10 tosecure the battery pack 14 in place if the biasing member 24 fails toprovide a locking engagement. The latches 22 a, 22 b are normally biasedaway from the casing 62 (i.e., away from each other) when squeezedtogether due to the resiliency of the material forming the outer housing60. Actuating (e.g., depressing) the actuators 58 a, 58 b moves thelatches 22 aa, 22 b toward the casing 62 (i.e., toward each other) toclear the respective latch contact surface 26 a, 26 b such that thebattery pack 14 may be pulled out of engagement with the biasing member24, out of the cavity 16 and away from the tool 10. Such an arrangementallows a user to quickly remove the battery pack 14 from the tool 10 forrecharging or replacement without the use of tools.

In operation, a user inserts the battery pack 14 in alignment with thechamfers 56 of the tool 10. Insertion of the battery pack 14 into thecavity 16 causes the biasing member 24 to deform radially outwardsagainst the biasing force of the biasing member 24 as the rails 20 a, 20b slidingly engage the projections 44 a, 44 b, respectively, of thebiasing member 24. When the battery pack 14 is fully inserted, thespring arms 24 a, 24 b are partially relieved as the projections 44 a,44 b are aligned with and extend into a clearance adjacent the rails 20.The projections 44 a, 44 b engage the ends of the rails 20 a, 20 b toretain the battery pack 14 in the tool 10. When the biasing member 24 isin engagement with the battery pack 14 to hold the battery pack 14 inplace, then a small clearance exists between the latches 22 a, 22 b andthe latch contact surfaces 26 a, 26 b such that the latches 22 a, 22 bare not in locking engagement with the latch contact surfaces 26 a, 26b. If the biasing member 24 disengages (e.g., fails, etc.), then thelatches 22 a, 22 b engage the latch contacting surfaces 26 a, 26 b toretain the battery pack 14 in the tool 10. The rubber pads 54 provide acushion to dampen vibrations transmitted from the tool 10 to the batterypack 14.

To remove the battery pack 14, the user depresses the actuators 58 a, 58b to move the latches 22 a, 22 b toward the casing 62 (i.e., toward eachother) to clear the latch contact surfaces 26 a, 26 b as the user pullsthe battery pack 14 out of the cavity 16. With the actuators 58 a, 58 bdepressed, the battery pack 14 may be pulled out of engagement with thebiasing member 24, out of the cavity 16 and away from the tool 10. Thechamfers 56 inhibit the user from being able to twist the battery pack14 while removing the battery pack 14 from the tool 10.

Although the invention has been described in detail with reference topreferred constructions, variations and modifications exist within thescope and spirit of one or more independent aspects of the invention asdescribed.

Thus the invention provides, among other things, a battery retentionsystem for a power tool. Various features and advantages of theinvention are set forth in the following claims.

What is claimed is:
 1. A battery retention system for a power toolhaving a motor, a drive mechanism coupled to the motor, and an outputelement coupled to the drive mechanism, the battery retention systemcomprising: a battery pack for powering the motor, wherein the batterypack is removably coupled to the power tool; a spring configured forcoupling the battery pack to the power tool in locking engagement toprovide power to the power tool, wherein the spring deforms against thebattery pack when the battery pack is fully inserted to reducetransmission of vibrations to the battery pack; and a latch configuredfor coupling the battery pack to the power tool in locking engagement toprovide power to the power tool independently from the spring as abackup to the spring; wherein the latch is not in locking engagementwhen the spring is in locking engagement.
 2. The battery retentionsystem of claim 1, wherein the latch is configured to couple the batterypack to the power tool in locking engagement to provide power to thepower tool when the spring fails to provide locking engagement.
 3. Thebattery retention system of claim 1, further comprising: a rail disposedon one of the battery pack or the power tool; wherein the springincludes a spring arm disposed on the other of the battery pack or thepower tool, wherein the spring arm engages the rail to retain thebattery pack on the power tool.
 4. The battery retention system of claim3, wherein the latch is formed on one of the battery pack or the powertool; and wherein the battery retention system further comprises alatch-receiving recess formed on the other of the battery pack or thepower tool; wherein the latch is received in the latch-receiving recessto retain the battery pack on the power tool.
 5. The battery retentionsystem of claim 4, wherein the recess includes a depth measured in thedirection of insertion of the battery into the power tool, wherein thedepth is dimensioned to provide a clearance between the latch and therecess in the direction of insertion when the battery pack is fullyinserted in the power tool and the first mating feature is in lockingengagement.
 6. The battery retention system of claim 1, furthercomprising a cushion disposed between the battery pack and the powertool for cushioning the battery pack against vibrations of the powertool.
 7. The battery retention system of claim 1, further comprising acavity for receiving the battery pack and a chamfer at an edge of thecavity leading into the cavity.
 8. A battery retention system for apower tool and a battery pack, the power tool having a motor, a drivemechanism coupled to the motor, and an output element coupled to thedrive mechanism, the battery retention system comprising: a latchreceiving recess for receiving a latch in locking engagement, the latchreceiving recess at least partially defined by a latch contact surface;and a mating feature independent from the latch receiving recess andconfigured for coupling the battery pack to the power tool in lockingengagement to provide power to the power tool; wherein the latchreceiving recess is configured such that the latch contact surface isspaced from the latch, so as to not engage the latch, when the matingfeature is in locking engagement; and wherein the mating feature isreleasable together with release of the latch for removing the batterypack from the power tool.
 9. The battery retention system of claim 8,further comprising a cavity for receiving the battery pack, wherein themating feature includes a protrusion in the cavity.
 10. The batteryretention system of claim 9, wherein the mating feature includes atleast one spring arm protruding into the cavity for engaging the batterypack.
 11. The battery retention system of claim 8, wherein the matingfeature includes at least one spring arm having a projection forengaging rails of the battery pack.
 12. The battery retention system ofclaim 8, wherein the mating feature includes a generally U-shaped springincluding two spring arms for engaging opposite rails of the batterypack.
 13. The battery retention system of claim 8, wherein the latchcontact surface is a first latch contact surface, the battery retentionsystem further comprising a second latch contact surface generallyopposite the first latch contact surface, wherein the mating feature isdisposed spaced from and in between the first and second latch contactsurfaces.
 14. The battery retention system of claim 8, furthercomprising an elastic pad for cushioning the battery pack againstvibrations of the power tool.